Generally, a display device that displays characters or figures by gas discharge is referred to as a plasma display panel (hereinafter "PDP"). The PDP typically serves as a display device for office automation.
FIG. 1 is a perspective view of a trigger discharge PDP disclosed in U.S. Pat. No. 4,562,434. The disclosed trigger discharge PDP comprises face plate 1 and rear plate 2, which are spaced at a predetermined distance, a plurality of X-Y matrix anodes 5 and cathodes 7, trigger electrodes 3 and a dielectric layer 4.
The trigger electrodes 3, the dielectric layer 4 and the cathodes 7 are disposed sequentially on the inner surface of the rear plate 2, and the anodes 5 are formed on the face plate 1 and extend in the direction perpendicular to the cathodes 7. At the same time, barrier ribs 6 are disposed in the same direction as the anodes 5, bridging the face and rear plates, separates the respective cathodes from the adjacent anodes.
In this PDP, an AC auxiliary discharge is generated between the trigger electrodes 3 and the cathodes 7. The dielectric layer interposed therebetween helps generate the DC main discharge between the cathodes 7 and the anodes 5, which are spaced apart from each other in a space filled with a gas layer. The trigger discharge is induced between the anodes 5 and the cathodes 7 as well as between the trigger electrodes 3 and the cathodes 7, thereby depositing wall charge on the surface of the insulating layer 4, which triggers discharges between the cathodes and the trigger electrodes to facilitate the main discharge between the anodes 5 and cathodes 7. Since the trigger discharge PDP triggers the main discharge by the wall discharge deposited on the surface of the dielectric layer 4, it advantageously prevents flickering at the initial stage of the main discharge, which problem occurs in non-triggering discharge PDP's. Further, the response speed increases, thereby realizing a high resolution image having a high scanning density.
However, since the trigger discharge occurs by AC currents through the dielectric layer interposed between the trigger electrodes and the cathodes, the intended characteristics are difficult to achieve requiring a dielectric layer formed to exacting specifications. Because the dielectric insulating layer separates the cathodes from the trigger electrodes and also serves as the structure on which the wall discharge is deposited to help trigger the main discharge, the dielectric constant must meet exacting standards, and its insulation destruction tolerance characteristics are also exacting. Further, a complex circuit for generating trigger pulses is required to cause the trigger discharge through the dielectric layer.
In addition, conventional trigger discharge PDP's require a very flat surface on the trigger electrodes in order to prevent the charge concentration in any particular region. This requires that the trigger electrodes be made of an expensive organic metal paste containing gold as a main ingredient.
Moreover, in this trigger discharge PDP, the distance between the cathodes and anodes must be maintained relatively narrow in order to induce sufficient trigger discharge. This requires that the widths of the cathodes be relatively narrow. However, if the widths of the cathode become narrow, the strength of the main discharge is lowered, resulting in reduced brightness of the discharge light.